import { createAnthropic } from '@ai-sdk/anthropic';
import { createDeepSeek } from '@ai-sdk/deepseek';
import { createOpenAI } from '@ai-sdk/openai';
import {
  generateText,
  streamText,
  stepCountIs,
  type ModelMessage,
  type Tool as AITool,
  type LanguageModel,
} from 'ai';
import type { Tool, ToolResult, Message, AgentConfig, ProviderType, UserInput, ContentBlock } from '../types/index.js';
import { buildZodSchema } from '../types/index.js';
import { ToolRegistry } from '../tools/registry.js';
import { SessionManager } from '../session/index.js';
import {
  CompressionManager,
  type TokenUsage,
  type CompressionConfig,
} from '../context/index.js';
import type { AgentInfo } from '../agent/types.js';

// Provider 配置
interface ProviderOptions {
  apiKey: string;
  baseUrl?: string;
}

// Provider 工厂函数类型
type ProviderFactory = (options: ProviderOptions) => (model: string) => LanguageModel;

// Provider 注册表
const providers: Record<ProviderType, ProviderFactory> = {
  anthropic: ({ apiKey, baseUrl }) => {
    const client = createAnthropic({ apiKey, baseURL: baseUrl });
    return (model) => client(model);
  },
  deepseek: ({ apiKey, baseUrl }) => {
    const client = createDeepSeek({ apiKey, baseURL: baseUrl });
    return (model) => client(model);
  },
  openai: ({ apiKey, baseUrl }) => {
    const client = createOpenAI({ apiKey, baseURL: baseUrl });
    return (model) => client(model);
  },
};

export class Agent {
  private getModel: (model: string) => LanguageModel;
  private config: AgentConfig;
  private conversationHistory: ModelMessage[] = [];

  // 工具注册表
  private registry: ToolRegistry | null = null;

  // 已发现的工具（通过 tool_search 发现的）
  private discoveredTools: Set<string> = new Set();

  // 兼容旧模式：直接注册的工具
  private legacyTools: Map<string, Tool> = new Map();

  // 会话管理器（可选）
  private sessionManager: SessionManager | null = null;

  // 压缩管理器
  private compressionManager: CompressionManager;

  // 当前 Agent 模式（null 表示默认模式）
  private currentAgentMode: AgentInfo | null = null;

  // 原始 system prompt（用于切换回 default 时恢复）
  private originalSystemPrompt: string;

  constructor(config: AgentConfig, compressionConfig?: Partial<CompressionConfig>) {
    this.config = config;
    this.originalSystemPrompt = config.systemPrompt;

    const providerFactory = providers[config.provider];
    if (!providerFactory) {
      throw new Error(`不支持的 provider: ${config.provider}`);
    }
    this.getModel = providerFactory({ apiKey: config.apiKey, baseUrl: config.baseUrl });

    // 初始化压缩管理器
    this.compressionManager = new CompressionManager(compressionConfig);
    // 设置模型用于生成摘要
    this.compressionManager.setModel(this.getModel(config.model));
  }

  /**
   * 设置工具注册表（新模式：支持动态工具发现）
   */
  setRegistry(registry: ToolRegistry): void {
    this.registry = registry;
  }

  /**
   * 设置会话管理器（启用会话持久化）
   */
  setSessionManager(manager: SessionManager): void {
    this.sessionManager = manager;
    // 从会话恢复状态
    const session = manager.getSession();
    if (session) {
      this.conversationHistory = [...session.messages];
      this.discoveredTools = new Set(session.discoveredTools);
    }
  }

  /**
   * 获取会话管理器
   */
  getSessionManager(): SessionManager | null {
    return this.sessionManager;
  }

  /**
   * 注册单个工具（兼容旧代码）
   */
  registerTool(customTool: Tool): void {
    this.legacyTools.set(customTool.name, customTool);
  }

  /**
   * 批量注册工具（兼容旧代码）
   */
  registerTools(tools: Tool[]): void {
    for (const tool of tools) {
      this.legacyTools.set(tool.name, tool);
    }
  }

  /**
   * 获取当前可用的工具
   * - 如果使用 registry 模式：返回核心工具 + 已发现的工具
   * - 如果使用旧模式：返回所有注册的工具
   * - 如果当前有 Agent 模式，应用工具过滤
   */
  private getAvailableTools(): Tool[] {
    let tools: Tool[];

    if (this.registry) {
      // 新模式：核心工具 + 已发现的工具
      const coreTools = this.registry.getCoreTools();
      const discoveredTools = this.registry.getTools([...this.discoveredTools]);
      tools = [...coreTools, ...discoveredTools];
    } else {
      // 旧模式：返回所有注册的工具
      tools = [...this.legacyTools.values()];
    }

    // 应用 Agent 模式的工具过滤
    if (this.currentAgentMode?.tools) {
      tools = this.filterToolsByAgentConfig(tools);
    }

    return tools;
  }

  /**
   * 根据 Agent 配置过滤工具
   */
  private filterToolsByAgentConfig(tools: Tool[]): Tool[] {
    const toolConfig = this.currentAgentMode?.tools;
    if (!toolConfig) return tools;

    let filteredTools = tools;

    // 如果设置了 enabled 列表，只保留这些工具
    if (toolConfig.enabled && toolConfig.enabled.length > 0) {
      const enabledSet = new Set(toolConfig.enabled);
      filteredTools = filteredTools.filter((t) => enabledSet.has(t.name));
    }

    // 如果设置了 disabled 列表，排除这些工具
    if (toolConfig.disabled && toolConfig.disabled.length > 0) {
      const disabledSet = new Set(toolConfig.disabled);
      filteredTools = filteredTools.filter((t) => !disabledSet.has(t.name));
    }

    // 如果禁止嵌套 Task，移除 task 工具
    if (toolConfig.noTask) {
      filteredTools = filteredTools.filter((t) => t.name !== 'task');
    }

    return filteredTools;
  }

  /**
   * 将工具转换为 Vercel AI SDK 的工具格式
   */
  private getVercelTools(): Record<string, AITool> {
    const vercelTools: Record<string, AITool> = {};
    const availableTools = this.getAvailableTools();

    for (const tool of availableTools) {
      const schema = buildZodSchema(tool.parameters);

      vercelTools[tool.name] = {
        description: tool.description,
        inputSchema: schema,
        execute: async (params) => {
          const result = await tool.execute(params as Record<string, unknown>);

          // 如果是 tool_search 调用，解析结果并注入发现的工具
          if (tool.name === 'tool_search' && result.success) {
            this.handleToolSearchResult(result.output);
          }

          return result;
        },
      } as AITool;
    }

    return vercelTools;
  }

  /**
   * 处理 tool_search 的结果，将发现的工具添加到可用列表
   */
  private handleToolSearchResult(output: string): void {
    // 解析输出，提取工具名称
    // 格式: "- tool_name: description [category]"
    const matches = output.matchAll(/^- (\w+):/gm);
    for (const match of matches) {
      const toolName = match[1];
      if (this.registry?.has(toolName)) {
        this.discoveredTools.add(toolName);
      }
    }
  }

  /**
   * 发送消息并处理响应（流式）
   * @param userMessage 用户消息文本或包含图片的 UserInput
   * @param onStream 流式输出回调
   */
  async chat(userMessage: string | UserInput, onStream?: (text: string) => void): Promise<string> {
    // 构建消息内容
    let messageContent: string | ContentBlock[];

    if (typeof userMessage === 'string') {
      // 纯文本消息
      messageContent = userMessage;
    } else {
      // 带图片的消息
      const blocks: ContentBlock[] = [];

      // 添加图片
      if (userMessage.images && userMessage.images.length > 0) {
        for (const img of userMessage.images) {
          blocks.push({
            type: 'image',
            image: img.data,
            mimeType: img.mimeType,
          });
        }
      }

      // 添加文本
      if (userMessage.text) {
        blocks.push({
          type: 'text',
          text: userMessage.text,
        });
      }

      messageContent = blocks.length === 1 && blocks[0].type === 'text'
        ? blocks[0].text
        : blocks;
    }

    // 添加用户消息到历史
    this.conversationHistory.push({
      role: 'user',
      content: messageContent,
    } as ModelMessage);

    const vercelTools = this.getVercelTools();
    let fullResponse = '';
    let responseMessages: ModelMessage[] = [];

    if (onStream) {
      // 流式模式
      const result = streamText({
        model: this.getModel(this.config.model),
        system: this.config.systemPrompt,
        messages: this.conversationHistory,
        tools: vercelTools,
        maxOutputTokens: this.config.maxTokens,
        stopWhen: stepCountIs(10), // 允许最多 10 轮工具调用
        onChunk: ({ chunk }) => {
          if (chunk.type === 'tool-call') {
            onStream(`\n[调用工具: ${chunk.toolName}]\n`);
          } else if (chunk.type === 'tool-result') {
            const output = (chunk as { output?: ToolResult }).output;
            if (output && typeof output === 'object') {
              if (output.success) {
                // 截断过长的输出
                const displayOutput =
                  output.output.length > 500
                    ? output.output.substring(0, 500) + '...(截断)'
                    : output.output;
                onStream(`[结果: ${displayOutput}]\n`);
              } else {
                onStream(`[错误: ${output.error}]\n`);
              }
            }
          }
        },
      });

      // 流式输出文本
      for await (const chunk of result.textStream) {
        fullResponse += chunk;
        onStream(chunk);
      }

      // 等待完成并获取完整的响应消息（包括工具调用和结果）
      const response = await result.response;
      responseMessages = response.messages as ModelMessage[];
    } else {
      // 非流式模式
      const result = await generateText({
        model: this.getModel(this.config.model),
        system: this.config.systemPrompt,
        messages: this.conversationHistory,
        tools: vercelTools,
        maxOutputTokens: this.config.maxTokens,
        stopWhen: stepCountIs(10), // 允许最多 10 轮工具调用
      });

      fullResponse = result.text;
      responseMessages = result.response.messages as ModelMessage[];
    }

    // 将完整的响应消息添加到历史（包括工具调用和结果）
    this.conversationHistory.push(...responseMessages);

    // 检查是否需要自动压缩
    if (this.compressionManager.shouldCompress(this.conversationHistory)) {
      const result = await this.compressionManager.compress(this.conversationHistory);
      if (result.freedTokens > 0) {
        this.conversationHistory = result.messages;
        if (onStream) {
          onStream(`\n[自动压缩: 释放了 ${(result.freedTokens / 1000).toFixed(1)}k tokens]\n`);
        }
      }
    }

    // 持久化会话
    await this.persistSession();

    return fullResponse;
  }

  /**
   * 持久化当前会话状态
   */
  private async persistSession(): Promise<void> {
    if (!this.sessionManager) return;

    await this.sessionManager.setMessages(this.conversationHistory);
    await this.sessionManager.setDiscoveredTools([...this.discoveredTools]);
  }

  /**
   * 清空对话历史和发现的工具
   */
  async clearHistory(): Promise<void> {
    this.conversationHistory = [];
    this.discoveredTools.clear();

    // 如果有会话管理器，创建新会话
    if (this.sessionManager) {
      await this.sessionManager.newSession();
    }
  }

  /**
   * 获取对话历史
   */
  getHistory(): Message[] {
    return this.conversationHistory
      .filter(
        (msg): msg is ModelMessage & { role: 'user' | 'assistant' } =>
          msg.role === 'user' || msg.role === 'assistant'
      )
      .map((msg) => ({
        role: msg.role,
        content: typeof msg.content === 'string' ? msg.content : JSON.stringify(msg.content),
      }));
  }

  /**
   * 获取当前可用工具的数量
   */
  getToolCount(): { core: number; discovered: number; total: number } {
    if (this.registry) {
      const coreCount = this.registry.getCoreTools().length;
      const discoveredCount = this.discoveredTools.size;
      return {
        core: coreCount,
        discovered: discoveredCount,
        total: coreCount + discoveredCount,
      };
    } else {
      return {
        core: this.legacyTools.size,
        discovered: 0,
        total: this.legacyTools.size,
      };
    }
  }

  /**
   * 获取当前上下文使用情况
   */
  getContextUsage(): TokenUsage {
    return this.compressionManager.calculateUsage(this.conversationHistory);
  }

  /**
   * 获取格式化的上下文使用情况（用于 CLI 显示）
   */
  getContextUsageFormatted(): string {
    return this.compressionManager.formatUsage(this.conversationHistory);
  }

  /**
   * 获取压缩管理器
   */
  getCompressionManager(): CompressionManager {
    return this.compressionManager;
  }

  /**
   * 手动压缩对话历史（用于 /compact 命令）
   */
  async compactHistory(): Promise<{ freedTokens: number; type: string }> {
    const result = await this.compressionManager.forceCompress(this.conversationHistory);
    if (result.freedTokens > 0) {
      this.conversationHistory = result.messages;
      await this.persistSession();
    }
    return {
      freedTokens: result.freedTokens,
      type: result.type,
    };
  }

  /**
   * 切换 Agent 模式
   */
  setAgentMode(agent: AgentInfo | null): void {
    this.currentAgentMode = agent;

    if (agent?.prompt) {
      // 切换到指定 Agent，使用其 prompt
      this.config = {
        ...this.config,
        systemPrompt: agent.prompt,
      };
    } else {
      // 切换回 default，恢复原始 prompt
      this.config = {
        ...this.config,
        systemPrompt: this.originalSystemPrompt,
      };
    }
  }

  /**
   * 获取当前 Agent 模式
   */
  getAgentMode(): AgentInfo | null {
    return this.currentAgentMode;
  }

  /**
   * 获取当前 Agent 名称
   */
  getAgentModeName(): string {
    return this.currentAgentMode?.name ?? 'default';
  }

  /**
   * 检查当前模型是否支持 vision（图片理解）
   */
  supportsVision(): boolean {
    const model = this.config.model.toLowerCase();

    // Anthropic Claude 模型支持 vision
    if (this.config.provider === 'anthropic') {
      // Claude 3 及以上版本支持 vision
      return model.includes('claude-3') || model.includes('claude-4');
    }

    // OpenAI GPT-4 系列支持 vision
    if (this.config.provider === 'openai') {
      // GPT-4o, GPT-4 Turbo, GPT-4 Vision 等支持
      return model.includes('gpt-4');
    }

    // DeepSeek 目前不支持 vision
    if (this.config.provider === 'deepseek') {
      return false;
    }

    return false;
  }

  /**
   * 获取当前配置
   */
  getConfig(): AgentConfig {
    return { ...this.config };
  }
}